Christian Ernst Stahl was a German botanist who was a native of Schiltigheim, Alsace.
He studied botany at the University of Strasbourg with Pierre-Marie-Alexis Millardet (1838-1902), and at the University of Halle under Anton de Bary (1831-1888).
He earned his doctorate in 1874, and later became an assistant to Julius von Sachs (1832-1897) at the University of Würzburg. Here, he also served as director of the botanical garden. During the winter of 1889-1890, he took a scientific expedition to Ceylon and Java, and in 1894 travelled to Mexico.
Two of his better-known students were Hans Adolf Eduard Driesch (1867-1941) and Hans Kniep (1881-1930). Stahl is remembered for his pioneer experiments in the field of ecophysiology, as well as research involving the developmental history of lichens. He was able to induce the synthesis of the lichen Endocarpon pusillum from spores and algal material, including formation of apothecia, and thus he made a strong experimental case for the hypothesis by Simon Schwendener (1829-1919) that lichens are twin fungal-algal organisms.
Other contributions by Stahl included studies concerning the influence of light on plants — he described the anatomy of sun and shade leaves. The effects of moisture and dryness on the formation of leaves, and the role of stomata in xerophytes and mesophytes. He conducted important research on the symbiotic relationship between mycorrhizal fungi and tree roots, and also worked on plant defense against snail and slug herbivory and a plethora of other botanical and ecological questions.